21047007 has 16 divisors (see below), whose sum is σ = 28563840. Its totient is φ = 13783392.

The previous prime is 21046997. The next prime is 21047017. The reversal of 21047007 is 70074012.

It is an interprime number because it is at equal distance from previous prime (21046997) and next prime (21047017).

It is not a de Polignac number, because 21047007 - 2¹² = 21042911 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55344 + ... + 55722.

It is an arithmetic number, because the mean of its divisors is an integer number (1785240).

Almost surely, 2^21047007 is an apocalyptic number.

21047007 is a deficient number, since it is larger than the sum of its proper divisors (7516833).

21047007 is a wasteful number, since it uses less digits than its factorization.

21047007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 21047007 is about 4587.7017121866. The cubic root of 21047007 is about 276.0981193882.

The spelling of 21047007 in words is "twenty-one million, forty-seven thousand, seven".